The present invention relates to a heating, ventilation, and air conditioning (“HVAC”) system for a vehicle. More particularly, the present invention relates to a vehicle that includes an insulated cabin and a HVAC system that conditions the cabin.
Large tractors or trucks (e.g., semi-tractors) are commonly used to transport cargo within a trailer or container. Existing tractors in a tractor-trailer combination typically include a cabin that is conditioned by multiple mechanically driven vapor compression air conditioning systems. In most tractors, the cabin is poorly insulated, and as a result, the multiple air conditioning systems cycle on and off very frequently. The frequent cycling of the air conditioning systems provides inefficient and expensive conditioning of the air in the cabin. The air conditioning systems and other components of the tractor and/or trailer are typically powered by a primary engine of the tractor when the vehicle is operating or moving. Some tractors include an auxiliary power unit that has a secondary engine that supplies power to the air conditioning systems and other components of the tractor when the primary engine is in a standby mode (i.e., when the primary engine is off).